A current mainstream communication device employs a configuration, in which a first body as an operation unit side used for operations by a user is connected via a hinge mechanism to a second body as a display side used for displaying a variety of information, and the bodies can be relatively moved around a rotational axis of the hinge mechanism so as to switch between an opened state and a closed state. Moreover, in such a communication device, a main antenna for a telephone call and/or data communication is disposed in one end of the first body or one end of the second body.
In addition, a technique is known in a communication device, for example, as disclosed in Patent Document 1, a reference potential portion (GND) of a circuit board built into the first body and a reference potential portion (GND) of a circuit board built into the second body are capacitively coupled. In this way, a reference potential (GND) of the entire device is stabilized at high frequency, and deterioration of the gain of the main antenna is prevented.
Here, the communication terminal according to Patent Document 1 includes: a first body; a second body; a connecting portion that connects the first body and the second body, so as to be capable of switching between a closed state in which the first body and the second body are superimposed with each other, and an opened state in which a degree of mutual superimposition is smaller than that of the closed state; conductive portions (circuit boards) that are disposed in the first body and the second body; and a first antenna that is disposed in the vicinity of the connecting portion. Furthermore, in order to capacitively couple the conductive portion in the first body and the conductive portion in the second body, the distance between them is no more than a predetermined distance L.    Patent Publication 1: Japanese Unexamined Patent Application Publication No. 2004-134975